DAX CALENDARAUTO function returns empty table when used in Power BI Desktop

Doh, followed along with the calendarauto example from the video (sqlbi.com) but no dates produced.

No syntax errors. Using 07.40 - Moving average.pbix

Table of Dates = CALENDARAUTO()

works just fine.

Tried other pbix files as well. 'New table' button was used :}

The following is the code I created that produces no syntax errors and no dates

Dates (CALENDARAUTO) =
    VAR _FirstDate_CustomerBirth = MIN ( 'Customer'[Birth Date] )
    VAR _FirstDate_ProductAvailable = MIN ( 'Product'[Available Date] )
    VAR _FirstDate_SalesDelivery = MIN ( 'Sales'[Delivery Date] )
    VAR _FirstDate_SalesOrder = MIN ( 'Sales'[Order Date] )
    VAR _FirstDate =
        IF ( _FirstDate_SalesOrder < _FirstDate_SalesDelivery, _FirstDate_SalesOrder, _FirstDate_SalesDelivery )
    VAR _DateTable =
         FILTER (
             CALENDARAUTO(),
             YEAR ( [Date] ) >= _FirstDate -- 'CALENDARAUTO'.[Date]
    )
RETURN
    ADDCOLUMNS(
        _DateTable,
        "Year", YEAR ( [Date] ),
        "Month", FORMAT ( [Date], "mmm" ),
        "Month Number", MONTH ( [Date] ),
        "Quarter", FORMAT ( [Date], "\QQ yyyy" )
    )